Big Pharma companies like Pfizer are now looking over their shoulder at startups like Berg who are using new techniques like artificial intelligence to develop drugs faster and cheaper. Photo: Reuters/Brendan McDermid

Pfizer Inc. (NYSE:PFE) opted out of bidding for Onyx Pharmaceuticals Inc. (NASDAQ:ONXX) this week, placing Amgen Inc. (NASDAQ:AMGN) in the lead to buy the cancer-drug maker, Reuters reported on Friday.

Shares in Onyx, valued at about $9.24 billion on Friday, fell nearly 2 percent on Friday after plummeting more than 3.3 percent on Thursday, when Reuters cited two unnamed sources saying Pfizer was no longer a suitor for the San Francisco company.

Onyx announced its sale process on June 30 after it rejected Amgen’s $120-per-share bid.